[PATCH V3 4/5] net: ethernet: ravb: Enable optional refclk

[Adam Ford]

For devices that use a programmable clock for the AVB reference clock,
the driver may need to enable them.  Add code to find the optional clock
and enable it when available.

Signed-off-by: Adam Ford <aford...@gmail.com>
---
V3:  Change 'avb' to 'AVB'
     Remove unnessary else statement and pointer maniupluation when 
     enabling the refclock. 
     Add disable_unprepare call in remove funtion.
      
V2:  The previous patch to fetch the fclk was dropped.  In its place
     is code to enable the refclk

diff --git a/drivers/net/ethernet/renesas/ravb.h 
b/drivers/net/ethernet/renesas/ravb.h
index 7453b17a37a2..ff363797bd2b 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -994,6 +994,7 @@ struct ravb_private {
        struct platform_device *pdev;
        void __iomem *addr;
        struct clk *clk;
+       struct clk *refclk;
        struct mdiobb_ctrl mdiobb;
        u32 num_rx_ring[NUM_RX_QUEUE];
        u32 num_tx_ring[NUM_TX_QUEUE];
diff --git a/drivers/net/ethernet/renesas/ravb_main.c 
b/drivers/net/ethernet/renesas/ravb_main.c
index bd30505fbc57..614448e6eb24 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2148,6 +2148,13 @@ static int ravb_probe(struct platform_device *pdev)
                goto out_release;
        }
 
+       priv->refclk = devm_clk_get_optional(&pdev->dev, "refclk");
+       if (IS_ERR(priv->refclk)) {
+               error = PTR_ERR(priv->refclk);
+               goto out_release;
+       }
+       clk_prepare_enable(priv->refclk);
+
        ndev->max_mtu = 2048 - (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
        ndev->min_mtu = ETH_MIN_MTU;
 
@@ -2260,6 +2267,9 @@ static int ravb_remove(struct platform_device *pdev)
        if (priv->chip_id != RCAR_GEN2)
                ravb_ptp_stop(ndev);
 
+       if (priv->refclk)
+               clk_disable_unprepare(priv->refclk);
+
        dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat,
                          priv->desc_bat_dma);
        /* Set reset mode */
-- 
2.25.1